Process for the production of lead tetra-alkyl



Patented June 18, 1929.

HEERT W. DAUDT, OF

EOINZ'I', AND KENNETH PENNS GROVE, r. MoNRoE, OF

AND A FRED a. manna, or caannvs PENNS GROVE, JERSEY, ASSIGNORS T0 E. I. DU PONT DE NEMOURS AND COMPANY, OF WILMINGTON, DELAWARE, A (JOB.-

PORATION OF DELAWARE.

PROCESS FOR THE PRODUCTION OF LEAD TETRA-ALKYL.

Np Drawing.

This invention relates to the process of producing lead tetra-alkyl by reaction between a mono-sodium lead alloy and an alkyl halide. More particularly it is concerned with the character and quantity of oxygen containing compound, or mixture of compounds best adapted to catalyze the reaction between mono sodium-lead alloy and an alkyl chloride. Ether and ethyl alcohol are the compounds preferred for efi'ecting the catalsis. y It has already been pointed out in 00- pending applications that the synthesis of lead alkyls from lead-sodium alloy and an alkyl bromide or an alkyl chloride may be controlled by the use in proper proportions of certain compounds which apparently act as catalysts for the reaction. Good examples.

of such compounds are water and the alcohols. These catalysts have a great influence on the reaction, their presence accelerating it at' lower temperatures and at the same time causing an increase in yield of tetra alkyl lead. On the'other hand, the presence of an excessive initial amount of water or of an alcohol will cause uneconomical evolution of hydrogen with apdiminution of yield of lead alkyl from that obtained when an optimum amount of hydrogen is evolved. It is obvious therefore that the most economical production oflead tetra-alkyls involves accurate regulation of the quantity of catalytically acting compounds employed. In general, the rate of reaction increases with a greater excess of catalysts. W

We have now discovered, however, that the process for making tetra-alkyl lead which involves the use of mono sodium-lead and an alkyl chloride is peculiarly sensitive to very small quantities of ethyl alcohol. The presence of this alcohol in very. small amounts equal to 0.005O.25% of the chloride has been found to materially increase the yield of tetraalkyl lead. Larger amounts, contrary to what might have been expected, in this instance have been found to causes, decrease in the yield of the desired product.

Similar experiments carried out with ether indicate that the reaction is not so sensitive to this substance. Very small amounts varying from 0.5% to 10% of the alkyl chloride have been found to produce substantial in- Application filed October 17, 1925. Serial No. 63,127.

creases in the yield, of tetra-alkyl lead, however.

In order to obtain the advantages accruing by the follow-.

our intention to limit ourselves to the specific proportions, temperatures and other details disclosed therein.

E wampZe.-To a mixture of 100 parts of mono sodium-lead alloy and 50 parts of ethyl chloride, contained in an autoclave, add 0.5 parts of ether which is known to contain 1.0% of alcohol. Rotate the autoclave in a water bath held at 40 6., for a period of four with more particular reference to the joint use.

of ether and alcohol as the catalytic compound, it will be understood that the invention covers broadly the use of alcohol or other separately in the manner described.

Where the product desired is lead tetramethyl, lead tetra-propyl or lead tetra-butyl instead of ethyl chloride, a stoichiometrically egulvalent uantity of the appropriate chlorlde should e employed.

We claim:

1. The process of producing tetra-alkyl lead which comprises reacting upon mono sodium-lead with analkylating agent in the presence of a very small but substantial quan trty of a catalyst of the group consisting of ethyl alcohol and ether. 7

2. The process of producing tetra-ethyl lead which comprises reactin upon a mono hours. Coolthe autoclave, remove the prodsodium-lead alloy with an et ylating agent.

sodium-lead alloy w1th an alkyl chloride in the resence of a Very small quantit of a cata yst of the group consisting of ethyl alcohol and ether. I

A. The process of producing tetra-ethyl lead whichcomprises reacting upon a mono sodium-lead alloy with anethylating agent in the presence of an amount of ethyl alcohol ranging between 0.005 and 0.25% of said agent.

5'. The process of producing tetra-alkyl lead which comprises reacting upon a mono sodium-lead alloy Withan alkyl chloride in the presence of an amount of ethyl alcohol ranging between 0.005 and 0.25% of said agent.

6. The process of producing tetra-ethyl lead which comprises reacting a'monosodium-lead alloy'with ethyl chloride in the presence of an amount of ethyl alcohol not more than 0.25% of the chloride. 7

7. In the manufacture of tetra-ethyl lead from a mono sodium-lead alloy and ethyl chloride the step of adding ethyl alcohol in an amount not more than 0,25%of the chloride.

8. The process of producing tetra-alkyl lead'which comprises reacting mono sodiumlead'alloy with an alkylating agent-in the presence of an ether solution of alcohol, in

which solution the alcohol content does not exceed one quarter of one percent of the amount'of alkylating agent.

9. The process as set forth in claim 8 in which the alcohol is dissolved in ether.

10. The processof producing tetra-ethyl alloy with ethylchloride in the comprising .ether and lead, which comprises reacting a mono soin which the alcohol content of the solution lies between 0.005 and 0.25% of the amount of ethyl chloride.

12. The process as set forth in claim 10 in which the ether does not exceed 10% and the alcohol does not exceed 0.25% of the amount of the ethyl chloride,

In testimony whereof We afiix our signatures.

I HERBERT W. DAUDT.

ALFRED E. PARMELEE. KENNETH P. MONROE. 

